# Adverse Outcome of a Solitary Fibrous Tumor Originating in the Bladder

## TL;DR

A rare bladder tumor called solitary fibrous tumor showed aggressive behavior despite treatment, leading to a poor outcome in a 68-year-old man.

## Contribution

This case highlights the potential for aggressive behavior in bladder-originating solitary fibrous tumors and the need for individualized treatment.

## Key findings

- A solitary fibrous tumor in the bladder invaded the prostate and recurred despite surgery and drug treatments.
- The patient's condition worsened with pazopanib, doxorubicin, and eribulin, leading to palliative care and death.
- The case underscores the lack of effective systemic therapies for these tumors and the need for tailored approaches.

## Abstract

Solitary fibrous tumors originating in the bladder are extremely rare. While generally associated with favorable outcomes, some show invasive behavior. We report a case of a solitary fibrous tumor originating in the bladder that was treated with multimodal therapy.

A 68‐year‐old male presented with urinary retention. Imaging revealed a well‐defined 6.0 cm mass compressing the prostate. A biopsy suggested stromal sarcoma. Robot‐assisted cystoprostatectomy was performed. Pathological examination revealed a solitary fibrous tumor originating from the bladder invading the prostate. Despite negative margins, lung nodules and a pelvic mass appeared 43 months postoperatively. Initially, these were treated with pazopanib, followed by doxorubicin and eribulin due to disease progression. The patient eventually transitioned to palliative care and passed away 69 months after diagnosis.

There are no effective systemic treatments for solitary fibrous tumors, which can lead to poor outcomes. Individualized treatment approaches are necessary.